1. Field of the Invention
The presently disclosed subject matter relates to an image processing method, an image processing device, a recording medium storing an image processing program and an image formation device, especially, a density unevenness correction technique based on the ejection characteristic of each nozzle.
2. Description of the Related Art
As an image formation device that records a color image on a recording medium, an inkjet recording device that ejects a color ink from an inkjet head is known. For instance, it adopts a configuration including the inkjet head corresponding to each color of cyan (C), magenta (M), yellow (Y) and black (K).
In the inkjet head, since there is variability in the ejection characteristic of each nozzle based on the manufacturing variability or the like, the correction value (correction coefficient) is prepared for every nozzle and density setting value (gradation value) beforehand, and correction processing is applied to image data by the use of this correction value.
Japanese Patent Application Laid-Open No. 2000-238299 discloses a printing device that prints a calibration pattern for density calibration on a print medium, detects variability in the ink use amount of each color from read data acquired by reading out that by a reading device, adds a modification to the color conversion table of corresponding element colors so as to overcome this variability, and thereby modifies the print data.
The print device described in Japanese Patent Application Laid-Open No. 2000-238299 foresees the time to fix each color ink on the print medium, acquires the deviation from the reference value of each color ink use amount, modifies print data so as to overcome this deviation, and corrects the gap of the color balance more accurately.